Structure and dynamics of polymer brushes near the θ point: A Monte Carlo simulation

Pik Yin Lai, Kurt Binder

研究成果: 雜誌貢獻期刊論文同行評審

264 引文 斯高帕斯(Scopus)

摘要

Grafted polymer layers under variable solvent conditions are studied by Monte Carlo simulations using the bond fluctuation model. Structural information such as monomer density profiles, brush thickness, mean-square displacement of monomers, and positions of the monomers along the chain are obtained for temperatures above, at, and below the θ point. In particular, the scaling of the brush thickness is formulated and verified by the simulation data. At the θ point, more extensive simulations are performed to investigate the structural and dynamical properties. While the brush thickness at the θ point agrees very well with the scaling and self-consistent field predictions, the latter deviate from our results for the monomer density profile and the distribution function of the free chain ends. It is not clear whether these deviations result from our chains being too short or from a basic inadequacy of the theory. For the dynamics at the θ point, both the relaxation of the chain configurations and the meansquare time displacement of the chains are studied. The relaxation time τ for a polymer brush of chain length N and surface coverage σ are found to behave as τ ∼ N 3σb with an apparent exponent b ≃t 1.6. For poor solvent conditions below the θ point, we find that the layer (with randomly fixed grafting sites) develops considerable lateral inhomogenity in its density, which has not been predicted by previous theories.

原文???core.languages.en_GB???
頁(從 - 到)586-595
頁數10
期刊Journal of Chemical Physics
97
發行號1
DOIs
出版狀態已出版 - 1992

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